KR19990032794U - Oxidation Catalytic Device of Diesel Engine - Google Patents

Abstract

The present invention is to install a cooler in the exhaust pipe or additionally equipped with an auxiliary catalyst to suppress the emission of harmful substances in the low-speed operating area of the engine, prevent oxidation of sulfuric acid in the high-speed operating area to prevent environmental pollution by the oxidation catalyst of the diesel engine The oxidation catalyst device is disposed in parallel with the exhaust pipe 4 and the first butterfly valves 42 and 142 rotatably mounted in the exhaust pipe 4 to control the discharge of the exhaust gas. Second butterfly valves 44 and 144 rotatably mounted in the bypass pipes 20 and 120 to control the discharge of exhaust gas, first butterfly valves 42 and 142 and second butterfly valves ( The first actuators 32 and 132 and the second actuators 34 and 134 which operate the 44 and 144, and the first actuators 32 and 132 are opened and closed by the negative pressure transmitted from the vacuum pumps 44 and 144. Second Actuator (34, 134) The first solenoid valves 22 and 122 and the second solenoid valves 24 and 124 to be operated, and the first solenoid valves 22 and 122 and the first solenoid valves 22 and 122 according to the engine speeds transmitted from the RPM sensors 52 and 152. It has a structure that includes ECUs 16 and 116 for selectively operating the first actuators 32 and 132 and the second actuators 34 and 134 by sending control signals to the two solenoid valves 24 and 124.

Description

Oxidation Catalytic Device of Diesel Engine

The present invention relates to an oxidation catalyst apparatus of a diesel engine, and more particularly, by installing a cooler in an exhaust pipe or additionally installing an auxiliary catalyst to suppress the emission of harmful substances in the low speed operation region of the engine and sulfuric acid in the high speed operation region. The present invention relates to an oxidation catalyst apparatus of a diesel engine that can prevent the occurrence of environmental pollution.

When the components of a diesel engine for a vehicle are roughly classified, a cylinder block having a plurality of cylinders integrally manufactured as a part constituting the engine main body, and a coolant passage through which a coolant passes is formed between each cylinder, It is arranged in the upper part to form a combustion chamber together with a piston, and comprises a cylinder head provided with various valve mechanisms and injection nozzles, and an oil pan attached to the lower part of the cylinder block to store engine oil.

When the exhaust gas discharged from the diesel engine is classified according to the emission source, the exhaust gas discharged into the atmosphere through the exhaust pipe after the mixture of fuel and air is combusted in the cylinder, and the evaporation gas from which gasoline in the fuel tank is evaporated, The clearance between the piston and the cylinder wall allows the mixer in the combustion chamber or unburned gas to be split into blow-by gas, which flows out of the crankcase.

Among them, a large amount of harmful gas is contained in the exhaust gas discharged from the engine through the exhaust manifold, and in order to prevent environmental pollution, these harmful gases are treated by a catalytic converter before being released into the atmosphere. It must be released by converting it into a harmless gas.

1 is a configuration diagram showing an exhaust system of a typical vehicle. The exhaust gas, which is combusted inside the engine and discharged through the exhaust manifold 2, flows into the catalyst 6 through the exhaust pipe 4 as the exhaust valve is opened. The exhaust gas discharged through the front exhaust pipe 4 contains various kinds of harmful substances, which are removed by the redox reaction in the catalyst 6. The exhaust gas which has passed through the catalyst 6 is sent to the first silencer 8 through the exhaust pipe 4 'to reduce noise, and then discharged to the outside via the tail pipe 4 ".

In the oxidation catalyst apparatus of a conventional diesel engine having such a configuration, since the area of the catalytic gas through which the exhaust gas passes is limited regardless of the operating region of the engine, the temperature of the exhaust gas in the low temperature region at low load with low engine operation speed Because of the low activity of HC and CO, the amount of emissions that cannot be processed and increased is increased, while the temperature of exhaust gas is high in the high temperature region under high load with high operating speed of the engine. As emissions increase, there is a problem of polluting the environment.

The present invention devised to solve such a problem is to install a cooler in the exhaust pipe or additionally equipped with an auxiliary catalyst to suppress the emission of harmful substances such as CO and HC in the low speed operating area of the engine and sulfur in the high speed operating area. It is an object of the present invention to provide an oxidation catalyst device of a diesel engine that can prevent the occurrence of environmental pollution by preventing the occurrence.

1 is a block diagram showing a conventional oxidation catalyst device,

2 is a block diagram showing an oxidation catalyst device according to an embodiment of the present invention,

Figure 3 is a block diagram showing an oxidation catalyst device according to another embodiment of the present invention.

♣ Explanation of symbols for main part of drawing ♣

2: Exhaust Manifold 4, 4 ', 4 ": Exhaust Pipe

6: Catalyst 8: Silencer

10: Chiller 14, 114: Vacuum pump

16, 116: ECU 20: Bypass pipe

22, 122: 1st solenoid valve 24, 124: 2nd solenoid valve

32, 132: 1st actuator 34, 134: 2nd actuator

42, 142: 1st butterfly valve 44, 144: 2nd butterfly valve

The above object of the present invention is to provide a catalyst for removing harmful substances contained in the exhaust gas discharged from the exhaust manifold through the exhaust pipe by the redox reaction, and a silencer for attenuating the exhaust sound of the exhaust gas passing through the catalyst. In the exhaust system of a diesel engine, the first butterfly valve is installed to rotate in the exhaust pipe to control the discharge of the exhaust gas, and the exhaust is discharged to be installed in the bypass pipe disposed in parallel with the exhaust pipe. The second and second actuators for operating the first and second butterfly valves, the first and second actuators for operating the first and second butterfly valves, and the negative pressure transmitted from the vacuum pump to open and close the first and second actuators. The first solenoid valve and the second solenoid valve to operate the Achievement by the oxidation catalyst device of the diesel engine comprising an ECU for selectively operating the first actuator and the second actuator by sending a control signal to the first solenoid valve and the second solenoid valve according to the number of revolutions of the engine do.

Hereinafter, the oxidation catalyst apparatus of the diesel engine according to the present invention will be described in detail with reference to FIGS. 2 and 3. (The same components as those of the conventional structure described with reference to FIG. 1 are denoted by the same reference numerals.)

2 is a block diagram showing an oxidation catalyst apparatus according to an embodiment of the present invention. Normally, the exhaust gas discharged through the exhaust manifold 2 flows into the catalyst 6 via the exhaust pipe 4 as the exhaust valve is opened. The exhaust gas discharged through the front exhaust pipe 4 contains various kinds of harmful substances, which are removed by the redox reaction in the catalyst 6. The exhaust gas which has passed through the catalyst 6 is sent to the first silencer 8 through the exhaust pipe 4 'to reduce noise, and then discharged to the outside via the tail pipe 4 ".

In the exhaust system of such a configuration, as a method for adjusting the purification capacity of the exhaust gas according to the rotational region of the engine, an embodiment of the present invention is connected to the bypass pipe 20 in parallel with the exhaust pipe (4) Next, the bypass pipe 20 was provided with a cooler 10 for cooling the exhaust gas.

In addition, in order to change the flow path of the exhaust gas, the first butterfly valve 42 is rotatably mounted in the exhaust pipe 4 so as to control the discharge of the exhaust gas, and in the bypass pipe 20 The second butterfly valve 44 was rotatably mounted to control the discharge of the exhaust gas.

The first butterfly valve 42 and the second butterfly valve 44 are opened and closed by the first actuator 34 and the second actuator 34, respectively. In addition, the first actuator 32 and the second actuator 34 are operated by the negative pressure transmitted from the vacuum pump 14, the negative pressure of the vacuum pump 14 is the first solenoid valve 22 and the second solenoid It is supplied and shut off by opening and closing the valve 24. The first solenoid valve 22 and the second solenoid valve 24 are each operated by electricity applied from the battery 50 under the control of the electronic control unit (ECU) 16.

The ECU 16 sends a control signal to the first solenoid valve 22 and the second solenoid valve 24 according to the engine speed transmitted from the engine speed (RPM) sensor 52. And selectively actuate the second actuator 34.

That is, the ECU 16 transmits a control signal to the second solenoid valve 24 in the low temperature operating region where the engine speed is low based on the signal transmitted from the RPM sensor 52. The second actuator 34 is operated by the operation of the second solenoid valve 24 so that the second butterfly valve 44 is opened as shown in phantom, while the first solenoid valve 22 has no control signal. Since the first butterfly valve 42 is not closed, the bypass pipe 20 is closed as shown by the solid line. Therefore, the exhaust gas discharged through the exhaust manifold 2 flows into the catalyst 6 through the open exhaust pipe 4 and then exits through the silencer 8 to the outside.

When the engine speed increases in such a state, the ECU 16 transmits a control signal sent to the second solenoid valve 24 when the engine speed exceeds a predetermined value based on a signal transmitted from the RPM sensor 52. On the other hand, the control signal is output to the first solenoid valve 22. Accordingly, while the first actuator 32 is operated by the operation of the first solenoid valve 22, the first butterfly valve 42 is opened as shown in the phantom line, while the second solenoid valve 24 is open to the second solenoid valve 24. Since no control signal is sent, the second butterfly valve 44 closes the exhaust pipe 4, as shown by the solid line. Therefore, the exhaust gas discharged through the exhaust manifold 2 flows into the cooler 10 through the open bypass pipe 20 and is cooled, and then passes through the catalyst 6 and the silencer 8 in order to the outside. To be discharged. Therefore, generation of sulfur by high temperature exhaust gas is suppressed.

3 is a block diagram showing an oxidation catalyst apparatus according to another embodiment of the present invention.

In this embodiment, in order to adjust the purification capacity of the exhaust gas according to the rotational area of the engine, while connecting the bypass pipe 120 in parallel with the exhaust pipe 4, at the same time assisted to the rear of the silencer (8) Catalyst 100 was further installed.

In addition, in order to change the flow path of the exhaust gas, the first butterfly valve 142 is rotatably mounted in the bypass pipe 120 so as to control the discharge of the exhaust gas. The second butterfly valve 144 is rotatably mounted to discharge the exhaust gas.

The first butterfly valve 142 and the second butterfly valve 144 are opened and closed by the first actuator 132 and the second actuator 134, respectively, as described with reference to FIG. 2. In addition, the first actuator 132 and the second actuator 134 is operated by the negative pressure transmitted from the vacuum pump 114, the negative pressure of the vacuum pump 114 is the first solenoid valve 122 and the second solenoid It is supplied and shut off by opening and closing the valve 124. The first solenoid valve 122 and the second solenoid valve 124 are respectively operated by electricity applied from the battery 150 under the control of the electronic control unit (ECU) 16.

The ECU 116 transmits a control signal to the first solenoid valve 122 and the second solenoid valve 124 according to the engine speed transmitted from the RPM sensor 152 to the first actuator 132 and the second actuator ( 134) selectively acts.

In the control, the ECU 116 transmits a control signal to the second solenoid valve 124 in the low temperature operating region where the engine speed is low based on the signal transmitted from the RPM sensor 152. As the second actuator 134 is operated by the operation of the second solenoid valve 124, the second butterfly valve 144 is opened as shown in phantom, while the first solenoid valve 122 has no control signal. Since the first butterfly valve 142 is closed, the bypass pipe 120 is closed, as shown by the solid line. Therefore, the exhaust gas discharged through the exhaust manifold 2 flows into the catalyst 6 through the open exhaust pipe 4, and the harmful substances are first purified, and then passed through the silencer 8 to the auxiliary catalyst ( 100) and purified secondarily. In this process, most of the harmful substances such as HC and CO are purified.

In this state, when the engine speed is increased, the ECU 116 transmits the control to the second solenoid valve 124 when the engine speed is greater than or equal to a predetermined value based on signals transmitted from the RPM sensors 52 and 152. While blocking the signal, a control signal is output to the first solenoid valve 122. Accordingly, while the first actuator 132 is operated by the operation of the first solenoid valve 122, the first butterfly valve 142 is opened as shown by the virtual line, while the second solenoid valve 124 Since no control signal is sent, the second butterfly valve 144 closes the exhaust pipe 4, as shown by the solid line. Therefore, the exhaust gas discharged through the exhaust manifold 2 is discharged through the open bypass pipe 120 and flows into the silencer 8. The exhaust gas introduced into the muffler 8 is supplied to the auxiliary catalyst unit 100 in a partially cooled state and purified, thereby suppressing the generation of sulfur due to the high temperature exhaust gas.

According to the present invention described above, a cooler is installed in the exhaust pipe so that the exhaust gas passes through the cooler in the high temperature region, and an additional auxiliary catalyst is additionally installed in the bypass pipe to exhaust the exhaust gas in the low speed operation region of the engine. By passing the gas through this auxiliary catalyst, there is an advantage that it is possible to suppress the emission of harmful substances such as CO and HC in the low temperature region and to prevent the generation of sulfur in the high speed region to prevent environmental pollution.

Claims (1)

Catalyst 6 for removing harmful substances contained in exhaust gas discharged from exhaust manifold 2 through exhaust pipe 4 by redox reaction, and exhaust noise of exhaust gas passing through catalyst 6 In the exhaust system of a diesel engine having a silencer (8) which damps the First butterfly valves 42 and 142 rotatably mounted in the exhaust pipe 4 to control the discharge of the exhaust gas; Second butterfly valves 44 and 144 rotatably mounted in the bypass pipes 20 and 120 disposed in parallel with the exhaust pipe 4 to control the discharge of the exhaust gas; First actuators 32 and 132 and second actuators 34 and 134 for operating the first butterfly valves 42 and 142 and the second butterfly valves 44 and 144; First solenoid valves 22 and 122 and second solenoid valves which are opened and closed by negative pressure transmitted from the vacuum pumps 14 and 114 to operate the first actuators 32 and 132 and the second actuators 34 and 134. (24, 124), The first actuators 32 and 132 send control signals to the first solenoid valves 22 and 122 and the second solenoid valves 24 and 124 according to the engine speeds transmitted from the RPM sensors 52 and 152. And an ECU (16, 116) for selectively operating the second actuator (34, 134).